Device against numbness able to help hand paddling stroke in water sports

ABSTRACT

The object of this invention relates to a hand device against numbness able to help hand paddling stroke in water sports comprising a closed loop strip of flexible material.

FIELD OF THE INVENTION

This invention belongs to the field of support devices for water sports such as surf, bodyboard, kneeboard on waves (surf kneeboard) and swimming.

PURPOSE OF THE INVENTION

The purpose of this invention is related to a device against numbness able to help hand paddling stroke in water adapted to wear in the hands of an athlete increasing, for example, the ability to propel a board through the liquid element; for example, this effect is also achieved by swimmers using the device when swimming in open water.

BACKGROUND OF THE INVENTION

Open water swimming is a water sport that demands the propulsion of the swimmer by known techniques using both hands and feet.

Surf is known as a water sport that involves sliding and making turns on a wave while the surfer or athlete is standing on a board.

Bodyboard is another water sport based on sliding on the surface or wall of the wave by means of a board, which is usually made of polyethylene or polypropylene and in which the person is normally lying face down on such board.

On another water sport that involves a board, kneeboard on waves (surf kneeboard), sliding on the waves is done while the athlete is kneeling on the board.

The last three sport examples have in common the use of boards to slide on waves.

The two latter water sports require that the person practicing them be safely grasped to the board either to stand on it or to modify the journey on the wave carrying he/she; in addition, it is also important that such person can provide the necessary propulsion to the board to catch the waves that allow him/her to slide on it, either standing or lying face down.

The person practicing the above mentioned water sports must perform swimming strokes by means of his/her arms and palms in order to achieve propulsion of his/her weight alone or together with the weight of the board used to catch the wave in which the sliding will take place.

When these athletes are exposed to cold water conditions for a long time, they lose heat causing their fingers to separate like claws; such finger separation produces the loss of an effective hand surface area affecting the board propulsion due to water runoff between fingers.

Such situation is also suffered by swimmers, especially in open water swimmers.

Enjoying water sports in recent years has grown and seen an increase in propulsion speed using flippers and other similar equipment such as gloves that increase the surface area of the hand by using devices with membrane between fingers (webbed gloves) and/or with solid surfaces to achieve the same effect, such devices were used despite being uncomfortable for surfing, bodyboarding and swimming athletes.

Regarding flippers, such equipment is typically used in feet to increase the effective surface area thereof to obtain an increase in speed through water. Other devices such as gloves are placed on athletes' hands to further increase their effective area to achieve the same purpose; however, these devices reduce hand mobility preventing effective board grasping in the sports above mentioned.

As it has been stated, among the known swimming devices for hands, there are webbed gloves with membrane between fingers adhering to all or some of the hand fingers or devices allowing attach surfaces to hands increasing its surface area in order to achieve greater propulsion.

Typically, a webbed glove includes receptacles for fingers between which there is a flexible material.

However, as it was explained, such accessories are uncomfortable for surfers who need to safely grab to the surfboard and they also have the problem that they need to prevent heat loss between fingers.

Neoprene gloves, commonly used in water sports, affect mobility when grasping boards and the water easily gets in them resulting on more weight for the athlete when performing strokes, propelling the board or swimming.

Among the devices of the above art that provide support for swimming are:

U.S. Pat. No. 3,698,026 provides a device that keeps your fingers together to achieve greater propulsion when swimming. This device has a substantially flat part having approximately the size of the width of the fingers and extending to cover the hand palm bypassing the fingers; the device is attached to the hand by straps that are fitted on the wrist. This device is uncomfortable for a surfer that needs to safely grab to the surfboard.

U.S. Pat. No. 2,692,995 relates to a flotation device to save people on shipwrecks and help swimmers comprising a sleeve made of a flexible floating material having a streamline cross section and a longitudinal inner edge on the sleeve covering the arm of the person wearing the device while the outer longitudinal edge forms a thin, flexible mesh that covers at least part of the hand and forearm of the person wearing the device; this sleeve has a hole in the inner longitudinal edge to pass through the thumb. This device makes it impossible for a surfer to comfortably grab the surf board and it does not allow the use of neoprene wetsuit with long sleeves, which is necessary when the sport is practiced in cold water.

U.S. Pat. No. 1,284,178 relates to a swimming membrane comprising a part made up by a single piece of folded material resulting in an outer layer and an inner layer; such layers are secured through their faces and they are provided with a plurality of tubular spaces to fit the swimmer's fingers, which are secured by cords passing through the base of the fingers and the outermost side of the fingers forming the membranes between tubular surfaces. This device increases the surface of the hand through the use of membranes but since the fingers are kept apart heat between them is lost.

U.S. Pat. No. 3,257,673 relates to a swimming glove comprising a set of tubular spaces for the fingers but that are open at the top and the hole on top is smaller than that of the bottom to ensure that hand fingers are fixed to the device; membranes are connected through such tubular spaces thus increasing the surface area of the hand achieving greater propulsion when swimming. Just like in the patent above mentioned, the fingers are kept apart producing heat loss between them, resulting in a disadvantage for surfers.

U.S. Pat. No. 1,051,169 relates to a swimming device comprising two plates linked together by means of joints that are secured to the palm of the hand and fingers by a strap; this device allows pivoting the outermost plate towards the innermost plate so as to achieve a shovel shape resulting in greater propulsion. This device makes it impossible for a surfer to comfortably grab his/her surf board.

U.S. Pat. No. 1,395,914 relates to a swimming device comprising a plate of rigid material delimiting the natural shape of the hand and cross divided near the knuckles in two sections pivoting together, the joining edges of such sections are cut so as to obtain free space in the knuckle area, a piece of flexible material covers the joining area to prevent hand damage. This device, similar to the one of the above patent, also makes it impossible for the surfer to comfortably grab his/her surfboard.

SUMMARY OF THE INVENTION

This invention relates to a hand device against numbness able to help hand paddling stroke in water sports comprising a closed loop strip of flexible material.

This device against numbness is able to help hand paddling stroke in water sports, the closed loop strip has a division formed by the joining of a part of its inner wall.

On some variants of the hand device against numbness able to help hand paddling stroke in water sports, the closed loop strip comprises a cylinder of flexible material with an elliptical base (1) and the division formed by the joining of a part of its inner wall generates two vertical holes passing through the cylinder of flexible material having an elliptical base (1).

In this hand device against numbness able to help hand paddling stroke in water sports, the vertical holes passing through the cylinder of flexible material having an elliptical base (1) are elliptical (2, 3).

On the above hand device against numbness able to help hand paddling stroke in water sports, one of the holes (2) has a size at least three times smaller than the other hole (3) and wherein the higher width of the cylinder elliptical base is about 6.25 times larger than its height.

On this variant of the hand device against numbness able to help hand paddling stroke in water sports, the smaller width of the elliptical base (1) of the cylinder of flexible material is 12.5 times smaller than the larger width of the elliptical base thereof.

Therein, the cylinder of flexible material having an elliptical base (1) has curved side walls (4).

On the hand device against numbness able to help hand paddling stroke in water sports, the curved side walls (4) bounded by the elliptical vertical holes (2, 3) and the cylinder of flexible material having an elliptical base (1) have a narrow section equivalent to about ⅓ of the height.

On the above hand device against numbness able to help hand paddling stroke in water sports, the wall (6) between the two elliptical vertical holes (2, 3) has a narrow section equivalent to about ⅓ of the height.

On this hand device against numbness able to help hand paddling stroke in water sports, the wall (6) between the two elliptical vertical holes (2, 3) generates a depression (7) on the outer wall of the cylinder of flexible material having an elliptical base (1).

On a variant of the hand device against numbness able to help hand paddling stroke in water sports, the index finger fits into the smaller elliptical vertical hole (2).

On such variant of the hand device against numbness able to help hand paddling stroke in water sports, the little, ring and middle fingers fit into the larger elliptical vertical hole (3).

On other variants of the hand device against numbness able to help hand paddling stroke in water sports, the larger elliptical vertical hole (3) has internal projections that establish the position of the little, ring and middle fingers within the larger elliptical vertical hole (3).

When the hand device against numbness able to help hand paddling stroke in water sports is a closed loop strip, it can be made of a material corresponding to an elastomer.

The device of this invention can be made of different elastomers: polymers, silicones, natural rubber, vinyl, latex, etc.

On another variant of the hand device against numbness able to help hand paddling stroke in water sports, the cylinder of flexible material having an elliptical base (1) can be made of an elastomer.

On these variants of the hand device against numbness able to help hand paddling stroke in water sports, the elastomer is: natural rubber or synthetic rubber. On the hand device against numbness able to help hand paddling stroke in water sports, the synthetic rubber can be silicone rubber.

BRIEF DESCRIPTION OF THE DRAWINGS

For better understanding of this description, the attached figures show a non-limiting embodiment of the object of this invention:

FIG. 1 shows a perspective, top and front views of the device against numbness able to help hand paddling stroke in water sports.

FIG. 2 shows the sizes of a variant of the device against numbness able to help hand paddling stroke in water sports.

FIG. 3 shows the differences between loss of propulsion (A) and efficient propulsion (B) wearing the device against numbness able to help hand paddling stroke in water sports of this invention. It is also shown the use of the invention device in the hand (C).

FIG. 4 shows the prior art of the device against numbness able to help hand paddling stroke in water sports corresponding to neoprene gloves and their disadvantages.

FIG. 5 shows the prior art of the device against numbness able to help hand paddling stroke in water sports corresponding to paddles increasing the hand surface and their disadvantages.

FIG. 6 shows the structural advantages of the device against numbness able to help hand paddling stroke in water sports of this invention.

FIG. 7 shows heat loss between fingers when they are apart.

FIG. 8 shows heat storage at hand when the device against numbness able to help hand paddling stroke in water sports of this invention is worn.

FIG. 9 shows the areas in which heat is maintained at hand when the device against numbness able to help hand paddling stroke in water sports of this invention is worn.

FIG. 10 shows four thermal pictures measured with infrared thermometer.

FIG. 11 shows an example of how the device is kept in turbulent water due to the greater grabbing achieved by means of the index finger.

FIG. 12 shows the temperature range in which the device should be worn.

FIG. 13 shows the different form variants that the device of this invention can have.

FIG. 14 shows a profile of the device stating how its section changes; at the bottom, the cross and longitudinal section thereof.

FIG. 15 shows a chart illustrating the results of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Open water surfers, bodyboarders and swimmers show resistance to wearing gloves (FIG. 4) in order to be as comfortable and efficient as possible; wearing gloves, such as neoprene gloves, does not allow adequate mobility and they get full of water, thus generating an extra weight when performing stokes or swimming; therefore, if gloves are not worn, greater propulsion when swimming and better management of the boards used for water sports are achieved. Long exposure to low temperatures is a common feature of this kind of sports and it produces tightening of the muscles of the hand, symptom known as claw. When muscles cool, they tighten generating involuntary tension of tendons that forces fingers to bend and spread apart. The ability of swimmers to control hand movement is affected by finger numbness, which causes lower propulsion effectiveness due to the microseparation of the fingers. This separation affects the strokes of surfer or swimmer, since due to the water runoff through the fingers, propulsion loses power (FIG. 3A).

Attempts have been made to increase the power of propulsion by means of devices that increase the surface area of the hand; these devices generate greater muscle wear, as they increase wrist pressure and wear; besides, when the stroke is finished, the arm needs to overcome an additional resistance force caused by the surface of such device when returning to the starting position (FIG. 5).

Moreover, the mere removal of water passing through the fingers prevents hand temperature loss, reducing also numbness. The solution found to the above problems is provided by the object of the invention comprising a hand device able to help hand paddling stroke in water sports including a closed loop strip which can be in a variant thereof a cylinder of flexible material having an elliptical base (1) and crossed through such elliptical base (1) by two elliptical vertical holes (2, 3) wherein one of the holes (2) has a size at least three times smaller than the other hole (3) and wherein the larger width of the elliptical base of the cylinder is about 6.25 times larger than the height thereof (FIG. 3C).

On other variants, the closed loop strip has a division formed by the joining of a part of its inner wall (FIG. 13).

The solution provided by the device of the invention also allows expanding the practice of the above mentioned water sports in cold water without wearing gloves by safely and softly keeping fingers together so as to prevent water passing through them (FIG. 3B).

The main effects achieved by the hand device able to provide sliding support for water sports of the invention are summarized as follows:

i) To counteract the symptoms of a hand claw produced by cold water

ii) To block the flow of cold water through fingers, reducing heat loss

iii) By keeping the fingers together, the device of the invention further allows relaxation of certain muscles of the forearm during the stroke, thus improving propulsion

The claw produced by numbness of the hand in cold water gets the fingers apart causing quick heat loss due to water runoff between the fingers (FIG. 7).

By keeping fingers together, the device against numbness able to provide sliding support for water sports of the invention maintains hand temperature even when sports are practiced in cold water (FIG. 8).

Due to direct finger contact by means of the device of the invention, heat transfer from one finger to the other one is produced, thus achieving greater conservation of thermal energy (FIG. 9), such as the same principle used by people when hugging when it is cold.

The hand device against numbness able to help hand paddling stroke in water sports of this invention substitutes neoprene gloves worn in cool to chilly water temperatures preventing the disadvantages that gloves cause, such as water filling and additional weight (FIG. 4).

The hand device against numbness able to help hand paddling stroke in water sports comprises a flexible material closed loop strip keeps the fingers of those persons practicing water sports together. The closed loop strip can be achieved through variants of the invention by different means known in the art.

This closed loop strip of flexible material has a division formed by the joining of a part of its inner wall that creates two holes of different sizes.

This closed loop strip of flexible material may comprise a cylinder of flexible material having an elliptical base (1) crossed from such elliptical base (1) by two elliptical vertical holes (2, 3) wherein one of the holes (2) has a size at least three times smaller than the other hole (3) and wherein the larger width of the elliptical base of the cylinder is about 6.25 times larger than its height.

When the device of the invention is worn, the index finger of the hand fits into the elliptical vertical hole (2), while the middle, ring and little fingers fit into the elliptical vertical hole (3), being the thumb free, thus allowing using it to grab any item, such as a surfboard.

Considering the index, middle, ring and little fingers of similar diameter, for the purpose of building the invention, it is stated that the elliptical vertical hole (2) wherein the index finger of the hand is placed has a size three times smaller than the elliptical vertical hole (3) wherein the middle, ring and little fingers are placed.

The separation between elliptical vertical holes (2) and (3) is extremely narrow in order to maintain the index finger next to the middle finger when the device of the invention is worn.

A suitable size that does not restrict holding movement of elements by the hand of the person wearing the device of the invention determines that the elliptical base of the cylinder of flexible material is approximately 6.25 times larger than its height.

A preferred variant of the invention is shown in FIG. 2 wherein the hand device against numbness able to help hand paddling stroke in water sports comprises a cylinder of flexible material having an elliptical base (1) that has the larger width of the elliptical base of the cylinder of 50 mm and the smaller width of the elliptical base of the cylinder of around 14 mm.

The height of the hand device against numbness able to help hand paddling stroke in water sports is of about 8 mm.

A preferred dimension of the device of the invention comprises the smaller width of the elliptical base (1) of the cylinder of flexible material 12.5 times smaller than the larger width of the elliptical base thereof. On it, the side curved walls (4) bounded by elliptical vertical holes (2, 3) and the cylinder of flexible material having an elliptical base (1) have a narrow section equivalent to about ⅓ of its height.

This narrow section of about ⅓ of the height is maintained in the wall (6) between the two elliptical vertical holes (2, 3) to ensure that the fingers remain together when wearing the device.

The cylinder of flexible material having an elliptical base (1) of the device of the invention is made of a polymeric material and the manufacturing process can be performed by extrusion or molding.

In another variant, it is preferred that the device of the invention has an opening (7) at the rear in the space between the two holes (2, 3) so as to modify the material thickness maintaining the profile thickness, since without it by having higher material thickness the elasticity of the device would be lesser. This eases that the greater tension is in the direction that gets the fingers together, and the lesser tension on the index and little fingers; this makes the device of the invention more comfortable.

The polymeric material comprising the device of the invention is selected from natural rubber and synthetic rubber.

Among the common synthetic rubbers used are ethylene acrylate rubber, polyester urethane, bromine isobutylene isoprene, chlorine isobutylene isoprene, polychloroprene, chlorosulfonated polyethylene, chloroprene, polyisoprene and silicone rubber, among others.

A preferred building material of the device of the invention comprises silicone rubber. In order to avoid hand damage, the hand device against numbness able to help hand paddling stroke in water sports has curved external walls (4) (see FIG. 1).

The profile of the device of the invention provides greater tension in the direction that is perpendicular to the fingers and lower tension in edges to ease blood circulation in the hand (FIG. 6).

The device of the invention is designed in order to include individual ring for the index corresponding to the elliptical vertical hole (2), which aims to provide more grabbing in turbulent water and to prevent detachment of the device (FIG. 11).

The profile of the device of the invention (thickness of the device) varies depending on its section (FIG. 14).

The thicker profile sections generate greater resistance when stretching, while the thinner areas stretch more easily; this eases that the greatest tension is in the direction joining the fingers and produces less tension on the little and index fingers (FIG. 14).

On some variants of the invention, the hand device against numbness able to help hand paddling stroke in water sports can include a logo (5) on the front for identification (FIG. 1).

The internal walls of the device against numbness of the invention may include internal projections that establish the position of the fingers inside it (top of FIG. 13).

On its unstretched shape, the outer perimeter of the closed loop strip of flexible material has a shape such that it can resemble the profile of an object with decorative purposes (such as a star, a heart, etc.).

Among the variants of the device of the invention that could be considered as an equivalent, there is a non-closed loop strip adapted for use on hands that could keep fingers together to achieve the same purpose described above.

Temperature Measuring Test with the Hand Device Against Numbness Able to Help Hand Paddling Stroke in Water Sports.

In order to determine how the hand of a swimmer maintains its temperature more effectively when wearing the device of the invention, the following test was performed by means of the infrared thermometer adaptable to mobile devices Phone Works (RYOBI™); such device enables measuring and recording temperature between −22° F. and 662° F. (FIG. 10).

By means of the infrared thermometer adaptable to mobile devices Phone Works, water temperature was measured without causing contact with the surface to be measured.

To perform this test, firstly, room temperature water and frozen cooling pads were placed in a glass container in order to lower the temperature of the liquid medium.

After 20 minutes, the cooling pads were removed and temperature was recorded: 49.5° F.

This temperature (49.5° F.) was considered as the temperature at which the hand device against numbness able to help hand paddling stroke in water sports should have been worn.

Temperatures were measured in both hands of a person having on his/her right hand the device against numbness of the invention and the left hand without the device against numbness of the invention.

To maintain consistency regarding measurements of the hands, both of them were registered between the middle finger and ring finger.

The values were as follows: temperature of left hand without device=79.5° F.; temperature of right hand with the device=79.7° F.

After this, at 49.5° F., both hand of the same person were immersed in the container with water; one hand with the device against numbness of the invention (right hand) and the other one (left hand) without the device against numbness of the invention.

After two minutes, the first measurement was registered for both hands, directing the infrared beam between the middle finger and ring finger.

Immersion and measurement tests were repeated at 4 minutes, 6 minutes, 8 minutes and 10 minutes, respectively.

The results are summarized in the following Table:

Temperature Temperature with without the device the device of the Immersion time of the invention invention  0 minutes 79.5° F. 79.7° F.  2 minutes 65.1° F. 68.0° F.  6 minutes 59.7° F. 63.7° F.  8 minutes 60.3° F. 63.9° F. 11 minutes 60.4° F. 61.7° F. 13 minutes 59.4° F. 63.3° F. 18 minutes 59.9° F. 60.8° F. 21 minutes 61.0° F. 61.7° F.

The results of the above table are shown in the chart illustrated in FIG. 15.

Conclusions:

As it can be noted by means of the above results, the hand device against numbness able to help hand paddling stroke in water sports of this invention maintains temperature more efficiently avoiding heat loss.

Please note that the above test was done at steady state, thus the heat produced by the hand paddling stroke work out is not taken into account. 

1. A hand device for avoiding numbness in the hand and helping hand paddling stroke in water sports, the hand device comprising a closed loop strip of flexible material with an inner wall and an outer wall, the inner wall and the outer wall having a height.
 2. The hand device according to claim 1, wherein the closed loop strip of flexible material has a division formed by a wall (6) extending between and joining opposite sides of the inner wall.
 3. The hand device according to claim 2, wherein, the closed loop strip of flexible material comprises a cylinder of flexible material, the cylinder of flexible material has an elliptical base (1), the elliptical base having a largest length and a largest width, the largest length being greater than the largest width and the division formed by the wall defines two vertical holes (2, 3) passing through the cylinder of flexible material.
 4. The hand device according to claim 3, wherein the two vertical holes passing through the cylinder of flexible material are, in cross-section, elliptical (2, 3).
 5. The hand device according to claim 4, wherein a first of the two vertical holes (2) has a size at least three times smaller than a second of the two vertical holes (3), and wherein the largest length of the elliptical base of the cylinder of flexible material is about 6.25 times larger than the height of the inner wall and the outer wall.
 6. The hand device according to claim 5, wherein the largest width of the elliptical base (1) of the cylinder of flexible material is 12.5 times smaller than the largest length of the elliptical base of the cylinder of flexible material.
 7. The hand device according to claim 6, wherein the cylinder of flexible material has, in a height direction of the outer wall, curved side walls (4) with a maximum length of the cylinder of flexible material being located intermediate an upper edge and a lower edge of the cylinder of flexible material.
 8. The hand device according to claim 7, wherein the curved side walls (4) bounded by the two vertical holes (2, 3) and the cylinder of flexible material have a section equivalent to about ⅓ of the height of the inner wall and the outer wall.
 9. The hand device according to claim 8, wherein the wall (6) extending between and joining opposite sides of the inner wall has a section equivalent to about ⅓ of the height of the inner wall and the outer wall.
 10. The hand device according to claim 9, wherein the outer wall of the cylinder of flexible material includes a depression (7) at a location where the wall (6) extending between and joining opposite sides of the inner wall joins one of the opposite sides of the inner wall, the depression (7) extending in the height direction of the outer wall.
 11. The hand device against numbness able to help hand paddling stroke in water sports according to claim 4, wherein an index finger of a hand is capable to fit into the first vertical hole (2).
 12. The hand device according to claim 4, wherein a little finger, a ring finger, and a middle finger of a hand are capable to fit into the second vertical hole (3).
 13. The hand device according to claim 12, wherein the second vertical hole (3) has internal projections (8) capable to establish the position of the little, ring and middle fingers.
 14. The hand device according to claim 1, wherein the closed loop strip of flexible material is made of an elastomer.
 15. The hand according to claim 4, wherein the cylinder of flexible material is made of an elastomer.
 16. The hand device according to claim 14, wherein the elastomer is natural rubber or synthetic rubber.
 17. The hand device according to claim 16, wherein the synthetic rubber is silicone rubber.
 18. The hand device according to claim 5, wherein the first vertical hole (2) is sized to fit an index finger of a hand and the second vertical hole (3) is sized to fit, at a same time, a little finger, a ring finger, and a middle finger of the hand. 19-20. (cancelled)
 21. A hand device for avoiding numbness in the hand and helping hand paddling stroke in water sports, the hand device comprising: a closed loop strip of flexible material defining a cylinder, the cylinder having an elliptical base (1) with a largest length and a largest width, the largest length being greater than the largest width, the cylinder having an inner wall and an outer wall, the inner wall and the outer wall having a height; a wall (6) extending between and joining a first location of the inner wall to an opposite, second location of the inner wall; and two vertical holes (2, 3) defined by the wall extending between and joining the first location of the inner wall to the opposite, second location of the inner wall, the two vertical holes (2, 3) passing through the cylinder of flexible material in a height direction of the inner wall and the outer wall, the two vertical holes (2, 3) being, in cross-section, elliptical (2, 3), wherein a first of the two vertical holes (2) has a size at least three times smaller than a second of the two vertical holes (3), wherein the largest length of the elliptical base is 6.25 times larger than the height of the inner wall and the outer wall, and the largest width of the elliptical base is 12.5 times smaller than the largest length of the elliptical base, and wherein the first vertical hole (2) is sized to fit an index finger of a hand and the second vertical hole (3) is sized to fit, at a same time, a little finger, a ring finger, and a middle finger of the hand.
 22. A hand device for avoiding numbness in the hand and helping hand paddling stroke in water sports, the hand device comprising: a closed loop strip of flexible material defining a cylinder, the cylinder having a base (1) with a largest length and a largest width, the largest length being greater than the largest width, the cylinder having an inner wall and an outer wall, the inner wall and the outer wall having a height; a wall (6) extending between and joining a first location of the inner wall to an opposite, second location of the inner wall; two vertical holes (2, 3) defined by the wall extending between and joining the first location of the inner wall to the opposite, second location of the inner wall, the two vertical holes (2, 3) passing through the cylinder of flexible material in a height direction of the inner wall and the outer wall, wherein a first of the two vertical holes (2) has a size at least three times smaller than a second of the two vertical holes (3), wherein the largest length of the base is 6.25 times larger than the height of the inner wall and the outer wall, and the largest width of the base is 12.5 times smaller than the largest length of the base, and wherein the first vertical hole (2) is sized to fit an index finger of a hand and the second vertical hole (3) is sized to fit, at a same time, a little finger, a ring finger, and a middle finger of the hand; and internal projections (8) located on the inner wall within the second vertical hole (3), the internal projections (8) located to establish positioning of the little finger, the ring finger and the middle finger of the hand within the second vertical hole. 